Nurses at the Kenema Ebola centre, located within a government-run hospital, are now calling for it to be relocated to another site and for MSF to take over the running of the facility, Tunis added.

Amid growing concern over the spread of the virus, activists have launched a campaign urging President Ernest Koroma to cancel an August trip to a US-Africa summit in Washington to deal with the crisis.

“He should cancel the trip and declare the Ebola outbreak a national emergency,” said journalist Lamrana Bah, who is leading the campaign.

Ebola is a form of haemorrhagic fever which is deadly in up to 90 percent of cases. It can fell victims within days, causing severe fever and muscle pain, vomiting and diarrhoea – and in some cases, organ failure and unstoppable bleeding.

According to the latest figures from the health ministry released on Wednesday, 422 cases of Ebola have been reported in Sierra Leone, leading to 143 deaths. In addition to Sierra Leone the virus has swept through Guinea and Liberia leaving more than 800 people dead, according to the World Health Organisation.